Inflatable pontoon boat

ABSTRACT

There is described a boat having two rubberized fabric inflatable pontoons and two separate open box-like hulls. The hull sections are joined to the pontoons by a beading on the pontoons which engages slots on either side of the hull sections. The pontoons are locked into position when they are inflated.

United States atet Forssell et a1.

INFLATABLE PONTOON BOAT US. Cl. 114/61, 9/2 A, 9/2 S Int. Cl 8631) 1/12,B63b 7/08 Field of Search 9/1 R, 2 AU, 11 A; 114/61,

References Cited UNITED STATES PATENTS 8/1956 Potts et al 114/61 'nlllll1111 3,812,805 1451 May 28, 1974 3,391,883 7/1968 Curtis 244/313,531,809 10/1970 Hegg...

3,608,112 9/1971 lrgens 9/2 A FOREIGN PATENTS OR APPLICATIONS 1,222,8138/1966 Germany 9 2 A Primary ExaminerGeorge E. A. Halvosa AssistantExaminer-Sherman D. Basinger Attorney, Agent, or FirmChristie, Parker &Hale [5 7 ABSTRACT There is described a boat having two rubberizedfabric inflatable pontoons and two separate open box-like hulls. Thehull sections are joined to the pontoons by a beading on the pontoonswhich engages slots on either side of the hull sections. The pontoonsare locked into position when they are inflated.

12 Claims, 7 Drawing Figures SATENTEBHAY 28 1974 SHEEY 1 [if 4 PAT VIA IENTED Y W? 3,812,805

sumanra INFLATABLE PONTOON BOAT FIELD OF THE INVENTION This inventionrelates to inflatable boats, and more specifically to a boat ofcatamaran design which can be readily assembled and disassembled.

BACKGROUND OF THE INVENTION The development of inflatable rafts andboats has received increasing attention because of the inherentadvantages of this type of craft and proven safety, lightness andcompactness, portability, load capacity and ruggedness under severeoperating conditions. However, prior designs of inflatable boats havesuffered from one or more of the following limitations. Theallinflatable boats, in which an air tube extends completely around theboat, lacks good performance and movement through the water. Their flat,flexible bot tom and shallow draft make them difficult to handle,provide poor passenger comfort in regard to standing or sitting, and theinternal flexibility makes it difficult to drive them under power sincethe distribution of the loads becomes difficult. At the same time theyare hard to row because of their ungainly shape and do not adaptthemselves to accepting a sailing rig.

For this reason, attempts have been made to combine the features ofrigid construction with an inflatable hull design in order to gainportability and compactness when not in use and at the same time achievesome of the performance characteristics of an entirely rigid boat.Attempts have been made to combine rigid transoms and rigidsuperstructure, adding a floor to the hull to add stiffness. Theinflatable portion of such boats may be in the form ofa single V- orU-shaped inflatable tube or may be in the form of two separateinflatable tubes in the form of pontoons. Known designs of this typehave not proved readily portable or have proved difficult to assembleand disassemble, have lacked adaptability to use either as a power boator as a sail boat, or not provided the passengers with adequate comfortand safety.

SUMMARY OF THE INVENTION The present invention is directed to animproved inflatable boat which combines a rigid hull structure withinflatable pontoons having the characteristics of a catamaran design.The boat design makes it extremely simple to assemble and disassemble,to store the boat in a small space when disassembled, and yet whenassembled to provide good performance when used either as a rowboat, apowerboat or a sailboat. The boat has a high safety factor in that itremains afloat even if air is lost from the inflated pontoons.

These and other advantages of the present invention are achieved by aboat which utilizes a pair ofinflatable pontoons which are joined whenin assembled condition by a pair of box-like rigid hull sections. Thesehull sections, when disassembled, are arranged to nest one inside of theother for compact storage. The hull sections are secured to andsupported between the pontoons by means of beading secured along theside of the pontoons which are pulled into slots extending along eitherside of the hull sections before the pontoons are inflated. After thepontoons are inflated, the pontoons wedge against the side of the hullsections, placing the beading under tension and securely locking thepontoons to the hull sections.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding ofthe invention reference should be made to the accompanying drawingswherein:

FIG. I is a top view of the boat when fully assembled;

DETAILED DESCRIPTION OF THE DRAWINGS Referring to the drawings indetail, the numeral 10 indicates generally the hull of the boat and inthe preferred embodiment includes two separate sections, the frontsection being indicated at 12 and the rear section being indicated at14. Each section is in the form of a substantially rectangular open box.However, as seen in the drawings, the two sections 12 and 14 are notidentical, but identical sections could be used if preferred. The fronthull section 12 includes a substantially flat bottom 16, a front wall18, rear wall 20, and side walls 22 and 24. The rear section 14similarly has a flat bottom wall 26, a front wall 28, rear wall 30 andside walls 32 and 34. It should be noted that the front wall 18 of thefront section and the side walls 22 and 24 of the front section, andalso side walls 32 and 34 of the rear section may be curved slightly toenhance the overall appearance of the boat. The side walls of bothsections are constructed with a step offset including a substantiallyhorizontal inwardly directed portion and a downwardly extending portion42 which joins the bottom wall, as best seen in FIG. 3. The top edges ofthe front and side walls are stiffened by an overhanging lip whichextends around the full perimeter of the front section, but which in theback wall of the rear section is interrupted by a wooden transom 44 thatcan be used for either mounting a small outboard engine (not shown) or arudder. See FIG. 7.

As best seen in FIG. 4, each of the hull sections is preferablyconstructed from a pair of vacuum molded inner and outer plastic shells43 and 45 which are joined together by a lap joint around the outerperiphery, as indicated at 46. The space between the inner and outershell is filled with a rigid or a semi-rigid foam plastic to addstrength and rigidity shown in FIG. 4. In addition, wood or plasticreinforcing stringers may be inserted between the two shells around thetop, as indicated at 47, to give added rigidity and strength to the hullsections. The rear hull section 14 is shaped so as to nest inside thefront hull section when the boat is disassembled to provide compactstorage. As further seen in FIG. 4, the inner shell of the rear sectionis further shaped to provide a raised seating area, as indicated at Thetwo hull sections 12 and 14 are supported by and at the same timeprovide a rigid connection between a pair of inflatable pontoons and 52,which are shown 3 in their assembled and inflated condition in FIGS. 1,2, and 3. Each pontoon is constructed from four longitudinal strips ofrubberized fabric. The four strips are shown in FIG. 6 after they arecut and laid out in a single plane. The two strips forming the top twoquarters of the pontoon are indicated at 54 and 56. The strips formingthe bottom two quarters of the pontoon are indicated at 58 and 60. Asbest seen in FIG. 6, the top strips 54 and 56 have a pair of straightedges and a pair of edges which are curved at either end to intersectthe straight edges. The bottom two strips are similarly formed with astraight edge and an edge which is curved at either end to interceptthis straight edge. The pontoon is formed by joining the straight edgesof the top two strips 54 and 56 together, the straight edge of the strip6 is joined to the curved edge of the strip 56 and the straight edge ofthe strip 58 is joined to the curved edge of the strip 54. Finally, thecurved edges of the strip 60 and 58 are joined to each other to provide.when inflated, a substantially cylindrical shaped pontoon whichterminates at a point at either end. As best seen in FIG. 2, the top ofthe pontoon lies in a common horizontal tangential plane out to the endsof the pontoon while the bottom of the pontoon curves upwardly at eitherend. The rear end may be rounded off more than the front end of thepontoon to provide an improved appearance. The edges of the strips maybe joined together by conventional techniques preferably utilizingreinforcing tape, such as indicated at 62, to overlap the seams. Whilethe pontoon can end in conventional conical tips closed by plugs or endcaps, an improved construction is realized when, as best shown at therear in FIGS. 1 and 2, substantially spherical end shapes are formed bymodifying the shapes of the tips of the four panels. The ends can thenbe covered by flat sealing patches, or the reinforcing tape 62 may becontinued across the ends, thus eliminating the complexity and potentialstructural weakness and leakage around end caps or plugs. This systempermits a pontoon shape which is both visually graceful and efficient inthe water.

Each pontoon is preferably divided into two separate airtightcompartments by a conical shaped diaphragm 64 made of rubberized fabricand which is adjoined to the interior surface of the strips forming thepontoon around the periphery of the base of the conical dia phragm.Suitable valves 66 and 68 are provided in each pontoon on either side ofthe conical diaphragm 64 through which air can be pumped into thepontoon to inflate it or through which air can be released from thepontoon to deflate it.

The manner in which the pontoons are joined to the hull sections is bestseen by referring to FIG. 4. Each of the hull sections has its outershell molded around an extruded aluminum or plastic tube 70, the tube 70being provided with a longitudinal slit 72. The tube 70 preferably runsthe full fore and aft length of the hull section and is positioned atthe juncture between the horizontal portion 40 and downwardly projectingportion 42 of the step offset. Each pontoon in turn is provided with abeading 74 running along a substantial length of the pontoon. Thebeading is preferably formed by a rope or solid plastic material whichis joined to the pontoon by a webbing 76. The webbing is sewn or moldeddirectly to the fabric of the pontoon.

When assembling the boat, the deflated pontoon is fastened to the hullsections by drawing the beading 74 through the tube 70, with the web 76extending through the slit 72. Index markings may be provided on thepontoon for correctly positioning the hull sections longitudinally ofeach of the pontoons. When the pen toons are then inflated, they assumea substantially circular cross-sectional shape. However, the beadingdistorts the shape of the pontoon so that, as the air pressure isincreased, the tension on the webbing 76 increases, thus firmly holdingthe pontoon against the horizontal and downwardly projecting portions 40and 42 of the hull section. This stressed connection between thepontoons and bull section prevents the pontoons from flexing sideways innormal use, giving the boat almost the same feel of rigidity andsolidity of a boat of conventional rigid non-inflatable design.

The pontoons can be inflated from any suitable pump or other source ofair. Preferably the pump should be one of high volume low pressuredesign, such as a bellows-type pump, since the inflated pressure needonly be about a pound per square inch.

The embodiment shown in FIGS. 1-3 shows the two hull sections positionedin abutting relationship. An I- beam member 80 may be inserted betweenthe two hull sections and pins, four of which are indicated at 82, maybe inserted through the flanges and the projecting lips at the top ofthe hull sections. The lips of the two hull sections are arranged to fitsnugly into the space between the flanges of the I-beam. This securesthe two hull sections together in a semi-rigid configuration in whichtwisting of the two hull sections is resisted but a hinging motion ispermitted to reduce stress as the boat rides over small waves. While thepreferred embodiment is to have two hull sections joined together asindicated, the boat can be assembled using only one hull section, ifdesired, or may be arranged with the hull sections spaced apart. Thespace between the two hull sections can be bridged, for example, by aflat board that can be held in place by the pins 82. This board (notshown) can be used as a seat to increase the seating capacity of theboat.

When the boat is not in use, as heretofore indicated, the pontoons aredeflated and folded by letting the air out of the pontoons andwithdrawing the beading 74 from the tubes 70. The two hull sections arenested one inside the other and the deflated pontoons are folded andstored within the hull sections. The entire assembly can be easilymounted on top of an automobile roof in the manner shown in FIG. 5.After the pontoons and other paraphernalia are stored in the nested hullsections, a fabric cover 86 is used to hold the stored materials inplace. The fabric cover is locked in position by snaps or otherconventional means. The nested hull sections can then be mounted on theroof of an automobile using conventional suction cups 88 and straps 90which clamp on the rain gutter of the automobile. Suitable holes may beprovided through the reinforced rim or lip of the hull sections topermit anchor pins 92 on which are mounted the suction cups 88 to engagethe hull sections and to hold the hull sections in place.

In addition to mounting a small outboard motor on the transom 44, theboat may be propelled by conventional oars. Holes 94 (see FIG. 1) areprovided in the rim of each hull section for receiving conventionaloarlocks.

In addition, as shown by FIG. 7, the boat may be operated as a sailboat.To this end a rudder 98 may be hingedly supported from the transom 44and operated by a tiller 1%. A mast step and centerboard assembly isprovided using welded steel-type sections as torque tubes. Thecenterboard and mast step assembly includes a first torque section 102which is welded or otherwise secured to the l-beam 80. Additionalcrossbracing between the l-beam and the downwardly projecting torquesection 102 may be provided to give lateral strength to the assembly. Atthe lower end of section 102 is welded a flat vertical plate 104 towhich a centerboard 106 is pivotally secured by pin H08. A horizontaltorque tube section 110 extends beneath the hull section l2 and isjoined to a vertical tube section 112 which is adapted to receive a mast114. The upper end of the tube 112 is provided with an integral plate116 which is bolted to the reinforcing lip at the front of the hullsection 12.

What is claimed is:

1. An inflatable boat comprising a pair of inflatable substantiallycylindrical shaped pontoons of flexible material, rigid hull meansincluding at least one unitary hull member having parallel sidesextending in a fore and aft direction a distance substantially greaterthan the diameter of the pontoons, each side having an indented stepextending the full length of the side, each forming an elongatedaligning groove for receiving one of the pontoons, the two aligninggrooves being parallel, radially extending webbing means secured to eachof the pontoons along a substantial length thereof, and means releasablysecuring the webbing means to the hull means within the grooves, theradial extent of the webbing being sufficiently short to be put intension by the inflation of the pontoons, wedging the inflated pontoonssecurely in the respective aligning grooves center of each of theindented steps, the beading sliding into the slots when the pontoons aredeflated, the beading securing the webbing under tension by theinflation of the pontoons to hold the pontoons wedged in place in thegrooves formed by the indented steps when the pontoons are inflated.

7. Apparatus of claim 6 wherein each pontoon when inflated issubstantially cylindrical in cross-section over a substantial portion ofits length, the inflated pontoons being deformed from the cylindricalshape by the tension of the beading and the wedging action of theindented steps.

8. A boat comprising a rigid unitary hull member formed with a pair ofelongated V-shaped parallel steps extending the length of the hull oneither side, each step having a narrow open-ended slit at the bottom ofthe V, a pair of elongated substantially cylindrical inflatable pontoonsmade of air-tight fabric, the V- shaped steps and associated slitsextending longitudinally a distance substantially greater than thediameter of the pontoons, each pontoon including a longitudinal flexiblewebbing secured to the pontoon and extending radially thereof, the outeredge of the webbing having a beading, the webbing extending through saidslits when the pontoons are in assembled position with the pontoonsextending along the respective steps, the webbing being placed intension between the beading and the pontoons when the associated pontoonis inflated within the confines of the V-shaped step.

9. The apparatus of claim 8 wherein said hull includes a plurality ofseparate sections positioned one behind the other, each section havingsteps which are formed by the indented steps to lock the pontoons inspaced apart parallel relationship.

2. Apparatus of claim 1 wherein the hull means includes two separatehull members positioned one behind the other in a fore and aftdirection, each member having equally spaced parallel sides with thegrooves of the two sections being aligned in a fore and aft direction.

3. Apparatus of claim 2 wherein the hull members are shaped such thatone member can be nested inside the other section when the boat isdisassembled.

4. Apparatus of claim 2 further including removable means for connectingthe two hull members together, said means connecting the aft portion ofthe forward hull member to the forward portion of the aft hull member ata position substantially the horizontal plane above the tangent to thetop of the two pontoons.

5. Apparatus of claim 2 wherein each hull member includes an inner andouter molded shell forming a double-walled structure, and plastic foammaterial filling the space between the shells, each hull member beingbuoyant in water when fully loaded independently of the pontoons.

6. Apparatus of claim 1 wherein said means for securing the webbing tothe hull means includes a beading attached to each pontoon and extendinglengthwise of the pontoon, the hull means having a longitudinal slotpositioned on the outside of the hull means at the aligned with thesteps of the adjacent section, whereby the sections are held inalignment by the pontoons engaging the aligned steps.

10. A boat comprising a rigid frame, a pair of inflatable substantiallycylindrical pontoons made of fabric, and means detachably connecting thepontoons to the frame in spaced apart parallel relationship, said meansincluding a radially extending webbing secured to and extendinglongitudinally of each pontoon, the frame including means on either sideof the frame forming a pair of surfaces extending in a fore and aftdirection of the boat and engaging an inflated pontoon tangentially ataccurately spaced positions on either side of the associated webbing,and means attached to the frame for holding the webbing in tension whenthe associated pontoon is inflated to urge the pontoon against said pairof tangential surfaces.

11. Apparatus of claim 10 wherein said means for means securing thewebbing against being withdrawn from the slot in a transverse directionwhile permitting movement of the webbing longitudinally of the passage.

l2. Apparatus of claim 10 wherein the frame includes an open box-shapedhull that is floatable independently of the pontoons, thepontoons wheninflated supporting said hull above the water.

1. An inflatable boat comprising a pair of inflatable substantiallycylindrical shaped pontoons of flexible material, rigid hull meansincluding at least one unitary hull member having parallel sidesextending in a fore and aft direction a distance substantially greaterthan the diameter of the pontoons, each side having an indented stepextending the full length of the side, each forming an elongatedaligning groove for receiving one of the pontoons, the two aligninggrooves being parallel, radially extending webbing means secured to eachof the pontoons along a substantial length thereof, and means releasablysecuring the webbing means to the hull meaNs within the grooves, theradial extent of the webbing being sufficiently short to be put intension by the inflation of the pontoons, wedging the inflated pontoonssecurely in the respective aligning grooves formed by the indented stepsto lock the pontoons in spaced apart parallel relationship.
 2. Apparatusof claim 1 wherein the hull means includes two separate hull memberspositioned one behind the other in a fore and aft direction, each memberhaving equally spaced parallel sides with the grooves of the twosections being aligned in a fore and aft direction.
 3. Apparatus ofclaim 2 wherein the hull members are shaped such that one member can benested inside the other section when the boat is disassembled. 4.Apparatus of claim 2 further including removable means for connectingthe two hull members together, said means connecting the aft portion ofthe forward hull member to the forward portion of the aft hull member ata position substantially the horizontal plane above the tangent to thetop of the two pontoons.
 5. Apparatus of claim 2 wherein each hullmember includes an inner and outer molded shell forming a double-walledstructure, and plastic foam material filling the space between theshells, each hull member being buoyant in water when fully loadedindependently of the pontoons.
 6. Apparatus of claim 1 wherein saidmeans for securing the webbing to the hull means includes a beadingattached to each pontoon and extending lengthwise of the pontoon, thehull means having a longitudinal slot positioned on the outside of thehull means at the center of each of the indented steps, the beadingsliding into the slots when the pontoons are deflated, the beadingsecuring the webbing under tension by the inflation of the pontoons tohold the pontoons wedged in place in the grooves formed by the indentedsteps when the pontoons are inflated.
 7. Apparatus of claim 6 whereineach pontoon when inflated is substantially cylindrical in cross-sectionover a substantial portion of its length, the inflated pontoons beingdeformed from the cylindrical shape by the tension of the beading andthe wedging action of the indented steps.
 8. A boat comprising a rigidunitary hull member formed with a pair of elongated V-shaped parallelsteps extending the length of the hull on either side, each step havinga narrow open-ended slit at the bottom of the V, a pair of elongatedsubstantially cylindrical inflatable pontoons made of air-tight fabric,the V-shaped steps and associated slits extending longitudinally adistance substantially greater than the diameter of the pontoons, eachpontoon including a longitudinal flexible webbing secured to the pontoonand extending radially thereof, the outer edge of the webbing having abeading, the webbing extending through said slits when the pontoons arein assembled position with the pontoons extending along the respectivesteps, the webbing being placed in tension between the beading and thepontoons when the associated pontoon is inflated within the confines ofthe V-shaped step.
 9. The apparatus of claim 8 wherein said hullincludes a plurality of separate sections positioned one behind theother, each section having steps which are aligned with the steps of theadjacent section, whereby the sections are held in alignment by thepontoons engaging the aligned steps.
 10. A boat comprising a rigidframe, a pair of inflatable substantially cylindrical pontoons made offabric, and means detachably connecting the pontoons to the frame inspaced apart parallel relationship, said means including a radiallyextending webbing secured to and extending longitudinally of eachpontoon, the frame including means on either side of the frame forming apair of surfaces extending in a fore and aft direction of the boat andengaging an inflated pontoon tangentially at accurately spaced positionson either side of the associated webbing, and means attached to theframe for holding the webbing in tenSion when the associated pontoon isinflated to urge the pontoon against said pair of tangential surfaces.11. Apparatus of claim 10 wherein said means for holding the webbingincludes means on either side of the frame forming a pair of tubularpassages extending in a fore and aft direction a distance substantiallygreater than the diameter of the pontoons, each of the passages having aslot for receiving the webbing, and means securing the webbing againstbeing withdrawn from the slot in a transverse direction while permittingmovement of the webbing longitudinally of the passage.
 12. Apparatus ofclaim 10 wherein the frame includes an open box-shaped hull that isfloatable independently of the pontoons, the pontoons when inflatedsupporting said hull above the water.